Improvement in expanding drills for boring blast-holes



J. JULIEN. Expanding- Drill for Boring Blast-Holes.

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UNITED STATES PATENT OFFICE.

JOHN JULIEN, OF DUBUQUE, IOWA.

IMPROVEMENT lN EXPANDING DRILLS FOR BORING BLAST-HOLES.

Specification forming part of Letters Patent No. 207,122, dated August20, 1878; application filed May 15, 1878.

To all whom it may concern.-

Be it known that I, JOHN JULIEN, of Dubuque, in the county of Dubuque,and in the State of Iowa, have invented certain new and usefulimprovements in drilling such holes in stone as can be used for a strongblast of powder; and do hereby declare that the following is a full,clear, and exact description thereof, reference being had to theaccompanying drawings, and to the letters of reference marked thereon,making a part of this specification.

The nature of my invention consists in the construction and arrangementof a drillingmachine for enlarging the lower or inner ends of holes madein stone for blasting purposes, so as to admit of a large charge ofpowder being placed therein, as will be hereinafter more fully setforth.

In order to enable others skilled in the art to which my inventionappertains to make and use the same, I will now proceedto describe itsconstruction and operation, referring to the annexed drawing, in which-Figure 1 is a longitudinal section of my in vention. Fig. 2 is a sideview of the lower part thereof.

A represents a tube of any suitable dimensions, having its upper endprovided with exterior screw-threads, and on the same is screwed ajam-nut, B, and upon the end of the tube is screwed a cap, 0, havingradial arms 0.

Through the center of the cap (1 is passed a rod, D, having a thumb-nut,F, screwed on its upper end. This rod extends down to the bottom of thetube, and its lower end is forked,

and has a curved bit or cutter, G, pivoted therein. This curved bit orcutter G is to project through a hole, a, in the side of the tube, nearthe lower end, and within the tube is fastened a slotted guide-piece, I,as shown, which also prevents the cutter being drawn up with the tube.

After the usual hole has been drilled this instrument is inserted insuch hole to any desired depth, and then rotated by any suitable means.The cutter G is then, by screwing down the thumb-nut F, gradually fedoutward through the slot a, so as to make an enlarged chamber at thebottom of the drilled hole, for the purpose of applying an increasedcharge of powder.

. I am aware that a reamer havin g enlargingbits, to be thrown out andin, are not new, and I do not claim such, broadly, as my invention.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is

The combination of the tube A, having slot to and slotted guide-piece I,the cap 0, rod 1), with thumb-nut F, and the curved bit or cutter Gr,all constructed substantially as and for the purposes herein set forth.

In testimony that I claim the foregoing I have hereunto set my hand this27th day of April, 1878.

JOHN JULIEN.

WVitncsses:

FRANK W. ALTMAN, HENRY KIENE.

